Embodiments of the present invention relate to digital broadcasts. More particularly, embodiments of the present invention relate to a device and system having conditional access to digital radio or digital television (TV) broadcasts.
There are several well-known digital radio and digital TV broadcast standards. In Europe, the digital radio broadcast is the DAB (Digital Audio Broadcasting) adopted by the ITU-R standardization body and by ETSI. The digital TV standard is DVB (Digital Video Broadcasting) in Europe, ATSC (Advanced Television Systems Committee) in the U.S., and ISDB (Integrated Services Digital Broadcasting) in Japan and South America. In addition to these standards, there are also mobile TV standards which relate to the reception of TV on handheld devices such as mobile phones or the like. Some well-known mobile TV standards are DVB-H (Digital Video Broadcasting-Handheld), CMMB (China), DMB (Digital Multimedia Broadcasting), and Mediaflo.
In most digital TV (DTV) broadcasting services, the service providers scramble and encrypt the transmitted data streams to protect the broadcasted content and require their customers or users to install “security protection” mechanisms to decrypt and descramble the content. Security protection mechanisms such as digital rights management enable users to store content. Conditional access systems are other security protection mechanisms that allow users to access and view content but may or may not record the viewed content.
In a typical pay-TV system, the conditional access software runs on a dedicated secure element implementing robust mechanisms so as to prevent a malicious entity (“hacker”) from gaining access to the broadcast system secret to decipher the TV content. The CA instruction code and keys provisioned by the CA provider adapted to ensure security are typically stored in a non-volatile memory, such as an EEPROM or Flash, which are relatively expensive and require a specifically tuned CMOS process for fabrication.
FIG. 1 is a block diagram of a conventional TV receiver 100 performing conditional access (CA) functions. Receiver 100 includes a TV demodulator 110 coupled to a suitable antenna 105 for receiving broadcast content. Demodulator 110 is connected to a secure element 120. The connection can be a proprietary interface or a standard interface. Secure element 120 may be provided by the service provider and controls access to a broadcast service by descrambling a transmitted broadcast. Secure element 120 may also hold service entitlement information controlled by the service provider. The service provider may communicate with the secure element using encrypted messages that carry descrambling keys and other service management information. Secure element 120 descrambles encrypted data streams received from the TV demodulator and provides the descrambled data streams to a video and audio decoder 130. A display 140 coupled to the video and audio decoder displays the decoded video and audio data streams. In general, secure element 120 may be provided in several forms and in multiple packaging options. For example, the secure element may be a dedicated surface mount device mounted on the receiver, a SIM card, a secure SD card, or a module. The secure element typically includes a crypto processor, a secure CPU, read-only memory (ROM), and electrical erasable and programmable ROM (EEPROM) or Flash, as shown in FIG. 1.
FIG. 2 is a block diagram of a conventional secure element 200 showing components incorporated in the secure element 120 of FIG. 1. Secure element 200 includes a demodulator interface 210 that establishes a physical and electrical connection with the demodulator 110. Typically, the physical and electrical connection is a proprietary hardware interface that enables a user to plug the secure element to the TV demodulator. Secure element 200 also includes a secure CPU 220 that is configured to decrypt messages or data streams that are transmitted by the service providers. Secure element 200 further includes a plurality of hardware accelerators 230-1, 230-2, . . . , 230n that assist the secure CPU for descrambling data streams and decode specific messages from the service provider. Secure element 200 additionally includes read-only memory 240 (ROM) and EEPROM/Flash 250. The ROM and EEPROM/Flash memory are programmed by the conditional access (CA) provider and contain CA firmware and decryption keys. When enabled by the user, CPU 220 executes program code stored in ROM and EEPROM/Flash memory and starts processing data streams received through the demodulator interface 210.
As shown in FIG. 1, the secure element 120 may include two physical interfaces, one for receiving encrypted data streams and the other one for sending decrypted data streams back to the demodulator. Other physical interfaces may exist for facilitating communication between the secure element and the demodulator.
It can be seen that the conventional secure element has a hardware architecture that is inflexible and adds costs to service providers. Furthermore, conventional techniques do not appear to address the concerns of service providers, CA operators, and content owners, specifically, at the point where content leaves the secure element.